Field of the Invention
The present invention relates to a transmitting direct mode communication apparatus, a receiving direct mode communication apparatus and communication path switching methods thereof. More particularly, the transmitting direct mode communication apparatus, the receiving direct mode communication apparatus and the communication path switching methods thereof accomplish switching of the communication path in a lower layer.
Descriptions of the Related Art
In the conventional Long Term Evolution (LTE) network technology, mobile apparatuses can communicate with each other directly through a specific protocol. For the direct mode communication apparatuses in such a direct mode communication system, firstly infrastructure connections are created via a backend network and then, when the direct mode communication apparatuses enter into each other's communication coverage and create direct communication connections therebetween, data can be exchanged via the direct mode communication connection.
Further speaking, a mobile apparatus which is to transmit data in an LTE network must categorize the data packets through use of a packet filter and, according to one of a source address, a source TCP/UDP port number, a destination address, a destination TCP/UDP port number of each packet and a combination thereof, determine a quality of service (QoS) of the data packets and determine which data radio bearer will be used for data transmission. It should be noted that, in LTE network, the mobile apparatus may have many activated packet filters at the same time, and these packet filters are usually collectively termed as Traffic Flow Template.
Unfortunately, in LTE network, direct mode connection is less stable than backend network connection. Therefore, data must still be transmitted via the infrastructure connection of the backend network when the direct communication connection between the direct mode communication apparatuses is interrupted. However, no primary connection switching mechanism is available in the conventional technology, so usually the infrastructure connection of the backend network must be reactivated in order to continue the data transmission when the direct communication connection between the direct mode communication apparatuses is interrupted.
Moreover, although management of communications across connections between the direct mode communication apparatuses can be accomplished by the application-layer session initiation protocol, the procedure is very complex and packet loss tends to occur due to long communication interruption time during the connection switching.
Accordingly, there is an urgent need in the art to provide a solution capable of switching the connection between direct mode communication apparatuses in the LTE network technology while avoiding the shortcomings of the complex connection switching procedure and the long interruption time during the connection switching